fix: offer recovery for blank desktop windows

React render failures now show a localized reload page, and renderer crashes offer native reload confirmation. Record renderer and load failures in existing diagnostics without automatic retry loops. Reload may lose unsaved input; the intermittent failure cause remains unconfirmed.

Release note: Recover from desktop rendering failures using a visible Reload action instead of being left without a recovery entry point.

src/renderer/src/AppErrorBoundary.css

@@ -0,0 +1,22 @@
+.app-error-recovery {
+  display: flex;
+  flex-direction: column;
+  align-items: flex-start;
+  justify-content: center;
+  width: 100%;
+  height: 100vh;
+  overflow: auto;
+  padding: var(--space-6);
+  background: var(--surface-raised);
+  color: var(--text-primary);
+  -webkit-app-region: no-drag;
+}
+
+.app-error-recovery h1 {
+  font-size: var(--font-page-title);
+}
+
+.app-error-recovery p {
+  color: var(--text-secondary);
+  margin-block: var(--space-4);
+}

src/renderer/src/AppErrorBoundary.test.tsx

@@ -0,0 +1,46 @@
+import { cleanup, fireEvent, render, screen } from '@testing-library/react'
+import { afterEach, describe, expect, it, vi } from 'vitest'
+import { AppErrorBoundary } from './AppErrorBoundary'
+
+function Broken(): never {
+  throw new Error('test render failure')
+}
+
+afterEach(() => {
+  cleanup()
+  localStorage.removeItem('goodbuddy.ui-locale')
+  vi.restoreAllMocks()
+  vi.unstubAllGlobals()
+})
+
+describe('AppErrorBoundary', () => {
+  it('leaves healthy children visible', () => {
+    render(<AppErrorBoundary><p>Working application</p></AppErrorBoundary>)
+    expect(screen.getByText('Working application')).toBeVisible()
+    expect(screen.queryByRole('alert')).not.toBeInTheDocument()
+  })
+
+  it.each([
+    ['zh-CN', '重新加载'],
+    ['en-US', 'Reload']
+  ])('recovers a failed tree without providers in %s and reloads only on click', (locale, label) => {
+    localStorage.setItem('goodbuddy.ui-locale', locale)
+    const log = vi.spyOn(console, 'error').mockImplementation(() => undefined)
+    const reload = vi.fn()
+    vi.stubGlobal('window', { location: { reload } })
+    render(<AppErrorBoundary><Broken /></AppErrorBoundary>)
+    expect(screen.getByRole('alert')).toBeVisible()
+    expect(screen.getByRole('main')).toHaveAttribute('lang', locale)
+    expect(log).toHaveBeenCalledWith('GoodBuddy UI failed', expect.any(Error), expect.stringContaining('Broken'))
+    expect(reload).not.toHaveBeenCalled()
+    fireEvent.click(screen.getByRole('button', { name: label }))
+    expect(reload).toHaveBeenCalledOnce()
+  })
+
+  it('still displays recovery when locale storage is unavailable', () => {
+    vi.spyOn(Storage.prototype, 'getItem').mockImplementation(() => { throw new Error('storage unavailable') })
+    vi.spyOn(console, 'error').mockImplementation(() => undefined)
+    render(<AppErrorBoundary><Broken /></AppErrorBoundary>)
+    expect(screen.getByRole('button', { name: '重新加载' })).toBeVisible()
+  })
+})

src/renderer/src/AppErrorBoundary.tsx

@@ -0,0 +1,39 @@
+import { Component, type ErrorInfo, type ReactNode } from 'react'
+import { loadUiLocalePreference, resolveUiLocale, systemUiLanguages } from './i18n/locale'
+import './AppErrorBoundary.css'
+
+export class AppErrorBoundary extends Component<
+  { children: ReactNode },
+  { failed: boolean }
+> {
+  state = { failed: false }
+
+  static getDerivedStateFromError(): { failed: boolean } {
+    return { failed: true }
+  }
+
+  componentDidCatch(error: Error, info: ErrorInfo): void {
+    console.error('GoodBuddy UI failed', error, info.componentStack)
+  }
+
+  render(): ReactNode {
+    if (!this.state.failed) return this.props.children
+
+    // Recovery must work even when the locale provider or application failed.
+    const locale = resolveUiLocale(loadUiLocalePreference(), systemUiLanguages())
+    const en = locale === 'en-US'
+    return (
+      <main className="app-error-recovery" lang={locale} aria-labelledby="app-error-title">
+        <div role="alert">
+          <h1 id="app-error-title">{en ? 'GoodBuddy could not display this page' : 'GoodBuddy 无法显示当前页面'}</h1>
+          <p>{en
+            ? 'Reload to try again. Unsaved input may be lost. If this happens again, quit and reopen GoodBuddy.'
+            : '请重新加载后重试。尚未保存的输入可能丢失。如果再次出现，请退出并重新打开 GoodBuddy。'}</p>
+        </div>
+        <button className="primary-button" type="button" onClick={() => window.location.reload()}>
+          {en ? 'Reload' : '重新加载'}
+        </button>
+      </main>
+    )
+  }
+}

src/renderer/src/main.tsx

@@ -4,6 +4,7 @@ import '@fontsource-variable/noto-sans-sc/wght.css'
 import 'katex/dist/katex.min.css'
 import './markdown-math.css'
 import App from './App'
+import { AppErrorBoundary } from './AppErrorBoundary'
 import { StorageUpgrade } from './StorageUpgrade'
 import { installBundledUiFonts } from './fonts'
 import { changeUiLocale } from './i18n'
@@ -51,12 +52,14 @@ installDocumentOcrBridge()
 
 createRoot(root).render(
   <StrictMode>
-    <UiLocaleProvider
-      initialPreference={initialUiLocalePreference}
-    >
-      {new URLSearchParams(window.location.search).get('storageUpgrade') === '1'
-        ? <StorageUpgrade />
-        : <App />}
-    </UiLocaleProvider>
+    <AppErrorBoundary>
+      <UiLocaleProvider
+        initialPreference={initialUiLocalePreference}
+      >
+        {new URLSearchParams(window.location.search).get('storageUpgrade') === '1'
+          ? <StorageUpgrade />
+          : <App />}
+      </UiLocaleProvider>
+    </AppErrorBoundary>
   </StrictMode>
 )